Patent application number | Description | Published |
20080262171 | Slurry Phase Polymerisation Process - A process comprising polymerising an olefin monomer optionally together with an olefin comonomer in the presence of a polymerisation catalyst in a diluent in a loop reactor which comprises at least 2 horizontal sections and at least 2 vertical sections to produce a slurry comprising solid particulate olefin polymer and the diluent wherein the Froude number in at least 20% of the length of the vertical sections of the reactor loop is less than 85% of the Froude number in at least 20% of the length of the horizontal sections of the loop is disclosed. | 10-23-2008 |
20090232711 | Slurry phase polymerisation process - A process comprising polymerising in a loop reactor an olefin monomer optionally together with an olefin commoner in the presence of a polymerisation catalyst in a diluent to produce a slurry comprising solid particulate olefin polymer and the diluent wherein the Froude number is maintained at or below 20 is disclosed. | 09-17-2009 |
20090252657 | Slurry phase polymerisation process - A process comprising polymerising an olefin monomer optionally together with an olefin comonomer in the presence of a polymerisation catalyst in a diluent in a loop reactor which comprises at least 2 horizontal sections and at least 2 vertical sections to produce a slurry comprising solid particulate olefin polymer and the diluent wherein the Froude number in at least 20% of the length of the vertical sections of the reactor loop is less than 85% of the Froude number in at least 20% of the length of the horizontal sections of the loop is disclosed. | 10-08-2009 |
20090312513 | Polymer stream transfer - Process for heating a polymer-containing stream being transferred from a polymerisation reactor to a degassing vessel, comprising passing the stream through a heater comprising a transfer line for the stream and means for heating the transfer line, wherein the ratio of the stream velocity at the outlet of the heater to that at the inlet, V | 12-17-2009 |
20100036078 | Polymer stream transfer - A process for heating a polymer-containing stream being transferred from a polymerisation reactor to a degassing vessel, comprising passing the stream through a heater comprising a transfer line for the stream and means for heating the transfer line, wherein the pressure drop in the heater is between 5% and 50%, preferably between 10 and 35%, of the total pressure drop between the polymerisation reactor and the entry to the degassing vessel. | 02-11-2010 |
20100174037 | SLURRY PHASE POLYMERISATION PROCESS - A polymerisation process is disclosed in which polyethylene is produced in slurry in a polymerisation reactor in the presence of a Ziegler Natta catalyst and an activator, and slurry containing the polymer is withdrawn from the reactor and transferred to a flash tank operating at a pressure and temperature such that at least 50 mol % of the liquid component of the slurry is withdrawn from the flash tank as a vapour and at least 98 mol %, more preferably at least 98.5 mol %, and most preferably at least 99.5 mol %, of the vapour withdrawn from the flash tank is capable of being condensed at a temperature of between 15 and 40C without compression, wherein a by-product suppressor, which reduces the amount of by-product formed per unit of polyethylene produced by at least 10% compared with an identical polymerisation process where the by-product suppressor is not present, is used in the reactor. | 07-08-2010 |
20100190921 | SLURRY PHASE POLYMERISATION PROCESS - Process for producing a multimodal polyethylene in at least two reactors connected in series, in which 20-80 wt % of a first polymer is made in suspension in a first reactor and 80-20 wt % of a second polymer is made in suspension in a second reactor in the presence of the first polymer, and a stream or slurry containing the resulting polymer is withdrawn from the second reactor and transferred to a flash tank operating at a pressure and temperature such that at least 50 mol % of the liquid component of the slurry, or the non-polymer component of the stream entering the flash tank, is withdrawn from the flash tank as a vapour, wherein the concentration in the stream or slurry entering the flash tank of components having a molecular weight below 50 g/mol, C | 07-29-2010 |
20100210796 | SLURRY PHASE POLYMERISATION PROCESS - Process for producing a multimodal polyethylene in at least two reactors connected in series, in which 20-80 wt % of a high molecular weight (HMW) polymer is made in suspension in a first reactor and 20-80 wt % of a low molecular weight (LMW) polymer is made in suspension in a second reactor in the presence of the HMW polymer, wherein the solids concentration in the second LMW reactor, defined as the mass of polymer divided by the total mass of slurry, is at least 35 wt %, most preferably between 45 wt % and 60 wt %, and/or the ratio of solids concentration in the first reactor to that in the second reactor is maintained at less than 1.0, preferably between 0.6 and 0.8, and further wherein the volume of the second reactor is at least 10%, preferably at least 30% and more preferably at least 50% greater than the volume of the first reactor. | 08-19-2010 |
20100249344 | SLURRY PHASE POLYMERISATION PROCESS - Process for producing a multimodal polyethylene in at least two reactors connected in series, in which 20-80 wt % of a high molecular weight (HMW) polymer is made in suspension in a first reactor and 20-80 wt % of a low molecular weight (LMW) polymer is made in suspension in a second reactor, wherein the ratio of the average activity in the LMW reactor to the average activity in the HMW reactor is from 0.25 and 1.5, where average activity in each reactor is defined as the rate of polyethylene produced in the reactor (kgPE/hr)/[ethylene concentration in the reactor (mol %)×residence time in the reactor (hours)×feed rate of catalyst into the reactor (g/hr)], residence time being defined as the mass of the polymer in the reactor (kg)/the output rate of polymer from the reactor (kg/hr), and wherein the volume of the second reactor is at least 10%, preferably at least 30% and more preferably at least 50% greater than the volume of the first reactor, and the ratio of length to diameter of the first reactor, L/D(1), is greater than that of the second reactor, U/D(2), and preferably at least 20% greater. | 09-30-2010 |
20100329934 | Slurry phase polymerisation process - A process comprising polymerising in a loop reactor an olefin monomer optionally together with an olefin commoner in the presence of a polymerisation catalyst in a diluent to produce a slurry comprising solid particulate olefin polymer and the diluent wherein the Fronde number is maintained at or below 20 is disclosed. | 12-30-2010 |
20110028684 | POLYMER STREAM TRANSFER - A process for heating a polymer-containing stream being transferred from a polymerization reactor to a separation zone or device, comprising passing the stream through at least two heaters operating in parallel, each heater comprising at least one transfer line for the stream and means for heating the transfer line, wherein the temperature of the polymer-containing stream at the outlet of all heaters is maintained above the dew point of the stream, and no heater has a volumetric flowrate of polymer-containing stream more than three times that of any other heater. | 02-03-2011 |
20110160420 | PROCESS FOR THE DEGASSING OF POLYMER POWER - The present invention provides a process for the production of a degassed polymer powder, which process comprises a) feeding i) a principal monomer, and ii) one or more comonomers fed in an amount of at least 5000 ppmw relative to the principal monomer feed rate, and iii) optionally one or more added alkanes having 2 to 10 carbon atoms, fed in an amount of at least 1000 ppmw relative to the principal monomer feed rate; into a polymerisation reactor wherein the monomer and comonomers react to form a polymer comprising residual hydrocarbons comprising one or more hydrocarbons having 3 to 10 carbon atoms, and b) passing the polymer to a degassing step wherein it is contacted with a purge gas to remove at least some of the residual hydrocarbons, characterised in that: 1) the G/P ratio in the degassing step is higher than a minimum G/P ratio, G being the purge gas mass flow rate in the degassing step and P being the polymer throughput of the degassing step, and 2) the purge gas has a concentration of critical hydrocarbon component which is lower than a maximum concentration of said critical hydrocarbon component in the purge gas, the critical hydrocarbon component being the heaviest hydrocarbon component selected from (i), (ii) and (iii) fed in step (a), which minimum G/P ratio and maximum concentration of said critical hydrocarbon component in the purge gas have been calculated based on the absorption coefficient, Kh, for the polymer powder to be degassed. | 06-30-2011 |
20110166313 | POLYMER STREAM TRANSFER - A process for heating a polymer-containing stream being transferred from a polymerization reactor to a separation zone or device is described, comprising passing the stream through a heater comprising at least one transfer line for the stream and means for heating the transfer line, wherein the average particle size of the solid polymer is less than 3 mm, the mass flowrate of the polymer-containing stream exiting the heater is no more than 15% greater than the mass flowrate exiting the reactor, and the average velocity of the polymer-containing stream at 80% along the length of the heated part of the transfer line measured from the transfer line inlet is at least 6 m/s, preferably at least 8 m/s and more preferably at least 10 m/s and the pressure drop across the transfer line is between 0.01 bar/m and 0.2 bar/m. | 07-07-2011 |